Field
Aspects of the present disclosure relate to semiconductor devices and, more particularly, to a folded metal-oxide-metal (MOM) capacitor that overlaps an on-chip inductor/transformer.
Background
Mobile radio frequency (RF) chips (e.g., mobile RF transceivers) have migrated to a deep sub-micron process node due to cost and power consumption considerations. Designing mobile RF transceivers is further complicated by added circuit functions for supporting communication enhancements, such as carrier aggregation. Further design challenges for mobile RF transceivers include using passive devices, which directly affect analog/RF performance considerations, including mismatch, noise, and other performance considerations.
Passive devices may involve high performance capacitor components. For example, analog integrated circuits use various types of passive devices, such as integrated capacitors. These integrated capacitors may include metal-oxide-semiconductor (MOS) capacitors, p-n junction capacitors, metal-insulator-metal (MIM) capacitors, poly-to-poly capacitors, metal-oxide-metal (MOM) capacitors, and other like capacitor structures. MOM capacitors are also known as vertical parallel plate (VPP) capacitors, natural vertical capacitors (NVCAP), lateral flux capacitors, comb capacitors, as well as interdigitated finger capacitors. MOM capacitors exhibit beneficial characteristics including high capacitance density, low parasitic capacitance, superior RF characteristics, and good matching characteristics without additional masks or process steps relative to other capacitor structures.
MOM capacitors are one of the most widely used capacitors due to their beneficial characteristics. MOM capacitor structures realize capacitance by using the fringing capacitance produced by sets of interdigitated fingers. For example, MOM capacitors harness lateral capacitive coupling between plates formed by metallization layers and wiring traces.
The design of mobile RF transceivers may include integrating MOM capacitors with inductors and/or transformers. Unfortunately, integrating MOM capacitors with inductors and/or transformers may degrade a performance of the inductors and/or transformers.